Navigate to the actual impl of comparison operators

[ChayimFriedman2]

Right now, if I "Go to" a comparison operator other than ==, and it is not overriden in the implementation for the type (that is, the type only implements eq() for PartialEq and not ne(), or only partial_cmp() and not lt(), le(), gt() or ge()) we navigate to the default implementation on PartialEq or PartialOrd. This does not help. We should navigate to eq() or partial_cmp() instead, or to the impl block.